LANDAU KLEFFNER SYNDROME

OVERVIEW

Landau Kleffner syndrome is characterized by subacute onset of
acquired aphasia in a child with normal previous development
and cognition. Seizures may not occur in all cases, and when present
are infrequent and self-limiting. However, there is a high risk of
significant residual language impairment.

NOTE Self-limiting refers to
there being a high likelihood of seizures spontaneously remitting at a
predictable age.

NOTE Landau Kleffner syndrome
is considered an 'epileptic encephalopathy'. This term denotes the
concept that the epileptic activity itself might directly contribute
additional cognitive and behavioral impairments over those expected
from the underlying etiology alone, and that suppression of epileptic
activity might minimize this additional impairment.

Clinical context

Landau Kleffner syndrome is characterized by subacute onset of
progressive aphasia in a child with previous age-appropriate language
development. The syndrome has onset between the ages of 2 and 8 years
(peak 5 to 7 years), or rarely later. The initial presentation may be with
progressive aphasia (40%), seizures or both. Both sexes are affected. The aphasia occurs as a consequence
of an acquired verbal auditory agnosia. Children become progressively
unable to comprehend spoken word, cease to understand when spoken to
and to respond verbally. The diagnosis is typically delayed as
children are thought to have acquired deafness, autistic regression or
mutism. Antecedent and birth history is normal. Neurological
examination and head size are normal. Behavioral (e.g. attention
deficit hyperactivity disorder, aggression), psychiatric and cognitive
disturbances are commonly observed in addition to language impairment.
Language impairment typically fluctuates. Seizures and EEG abnormality
resolve with age in most cases, however residual language impairment
is seen in the majority (>80%) and may be severe (especially if
onset is earlier).

CAUTION Children who have
not developed language before onset of seizures should generally not
be considered for this syndrome.

CAUTION Children with
autism may show language regression, however this typically occurs
earlier (< 2 years), prior language development is typically
abnormal and regression in language is not compensated for by
non-verbal communication.